Testosterone is a hormone that is necessary for both men and women. It contributes to muscle mass, strength, endurance, decreased fat, and increased exercise tolerance. Testosterone improves libido and sexual function. At optimal levels, testosterone increases bone density and reduces the risk of osteoporosis. It has many positive effects on the cardiovascular system. Testosterone’s vasodilatory effects help lower blood pressure, improving or protecting against hypertension and heart disease. It lowers LDL (bad) cholesterol and increases HDL (good) cholesterol levels. Testosterone reduces insulin resistance, body fat, and arthritis. It improves skin tone, collagen production, and healing capacity. It decreases inflammation and has been shown to reduce degenerative joint disease. Testosterone is also a great mood enhancer and imparts a sense of well-being in men and women.